A symposium under the auspices of the Society of General Physiologists is planned for September 21-24, 1978, at the Marine Biological Laboratory, Woods Hole, Massachusetts. The general topic of the symposium will be membrane-membrane interactions. This topic will be focused on three areas: 1) general related features of membrane systems, such as the structure and function of membrane proteins, membrane lipids, and the use of model membrane systems (liposomes); 2) short-term or transient interactions between cells, including secretion, phagocytosis, pinocytosis, cell fusion, fertilization, etc.; and 3) long-term or stable interactions between cells, including cell junctions, myelin, chloroplast membranes, etc. The program will be conducted during four morning sessions. Afternoon sessions will consist of contributed papers, mostly related to the central theme of the symposium. Prompt publication (Spring, 1979) of the invited papers is planned by Raven Press.